1. Field of the Invention
This invention relates to a surface-wave driven motor for driving a moving member by an elastic wave of a high frequency.
2. Description of the Prior Art
Any of electric motors heretofore used most generally utilizes an electromagnetic force and therefore has great limitations in shape and materials. Also, they use a winding constituting an electromagnet and use a permanent magnet of rare earth to obtain a high output, and this has also led to a limitation in cost.
For such a situation, in recent years, actuators have been developed to replace electromagnetic type motors, and as one of them, an ultrasonic driven motor utilizing an ultrasonic wave has been conceived. This ultrasonic driven motor is regarded as being much more advantageous than the conventional motors in shape, efficiency, cost, etc. and as a basic research report thereof, IBM Technical Disclosure Bulletin Vol. 16, No. 7, etc. have been published from IBM, Inc., U.S.A. As an example of the trial manufacture of this ultrasonic driven motor, a surface-wave type ultrasonic driven motor (hereinafter referred to as the surface-wave driven motor) in which a piezo-electric element or the like is used to create a surface wave on the surface of a resilient member and drive a rotor urged against this surface has been devised and already announced.